Question

Question 15 of 40

For which sample size (n) and sample proportion () can a normal curve be
used to approximate the sampling distribution?
O A. n = 28; = 0.3
O B. n = 28; p = 0.9
O c. n = 32; p = 0.4
O D. n = 32; p = 0.2

Answer 1

Option C: n = 32; p^ = 0.4

Explanation:

The normal curve can be used in this case if; np ≥ 10 or n(1 - p) ≥ 10

A) For n = 28 and p = 0.3;

np = 28 × 0.3 = 8.4 < 10

Thus, it can't be used.

B) For n = 28 and p = 0.9;

np = 28 × 0.9 = 25.2 > 10 Ok

n(1 - p) = 28(1 - 0.9) = 2.8 Not Ok

Thus, it can't be used

C) For n = 32 and p = 0.4

np = 32 × 0.4 = 12.8 > 10 Ok

n(1 - p) = 32(1 - 0.4) = 19.2 > 10 Ok

Thus, it can be used

D) For n = 32 and p = 0.2

np = 32 × 0.2 = 6.4 < 10 Not Ok

Thus it can't be used.